Stable carbon and nitrogen isotopic composition of bulk aerosol particles in a C4 plant landscape of southeast Brazil

The carbon and nitrogen isotopic compositions of aerosol particles collected in the Piracicaba region, where C4 plants like sugarcane and pasture dominate the land cover, were measured. For comparison, aerosol particles were also analyzed from the Santarem region, Amazon basin, where the main land cover is primary forest. The average delta(13)C value of samples collected in Piracicaba was equal to -20.9 +/- 0.8parts per thousand.. The average delta(13)C of samples collected in Santarem was almost 5parts per thousand smaller than in Piracicaba (-25.8 +/-0.5parts per thousand). This difference between the two sites was attributed to the presence of C4 material in Piracicaba aerosol particles. On the other hand, there was no statistical difference between the average delta(15)N values observed in Piracicaba (10.6 +/- 2.8parts per thousand) and Santarem (11.5 +/- 2.1parts per thousand). The delta(13)C and delta(15)N values of aerosol particles collected in Santarem were higher than vegetation tissues and soil organic matter, which are the potential sources of organic matter to aerosol particles. (C) 2002 Elsevier Science Ltd. All rights reserved.